Asymmetric Supernovae, Pulsars, Magnetars, and Gamma‐Ray Bursts

We outline the possible physical processes, associated timescales, andenergetics that could lead to the production of pulsars, jets, asymmetricsupernovae, and weak gamma-ray bursts in routine circumstances and to amagnetar and perhaps stronger gamma-ray burst in more extreme circumstances inthe collapse of the bare core of a massive star. The production of aLeBlanc-Wilson MHD jet could provide an asymmetric supernova and result in aweak gamma-ray burst when the jet accelerates down the stellar density gradientof a hydrogen-poor photosphere. The matter-dominated jet would be formedpromptly, but requires 5 to 10 s to reach the surface of the progenitor of aType Ib/c supernova. During this time, the newly-born neutron star couldcontract, spin up, and wind up field lines or turn on an alpha-Omega dynamo. Inaddition, the light cylinder will contract from a radius large compared to theAlfven radius to a size comparable to that of the neutron star. This willdisrupt the structure of any organized dipole field and promote the generationof ultrarelativistic MHD waves (UMHDW) at high density and Large AmplitudeElectromagnetic Waves (LAEMW) at low density. The generation of the these waveswould be delayed by the cooling time of the neutron star about 5 to 10 seconds,but the propagation time is short so the UMHDW could arrive at the surface atabout the same time as the matter jet. In the density gradient of the star andthe matter jet, the intense flux of UMHDW and LAEMW could drive shocks,generate pions by proton-proton collision, or create electron/positron pairsdepending on the circumstances. The UMHDW and LAEMW could influence thedynamics of the explosion and might also tend to flow out the rotation axis toproduce a collimated gamma-ray burst.Comment: 31 pages, LaTeX, revised for referee comments, accepted for ApJ, July 10 issu